The present invention relates to a retainer clip for holding a gasket centered between the sealing beads of tube ends in a face seal fitting.
Retainer clips for holding a gasket between sealing beads projecting from the ends of tubes in a face seal fitting are known. Such fittings include the type used in applications requiring special cleanliness, such as the manufacture of semiconductor devices. U.S. Pat. No. 4,838,583 to Babuder et al. discloses one such retainer clip. That retainer clip comprises a single annular structure which fits around the gasket and around one of the tube ends in a face seal fitting. A problem with the known retainer clips is that the gaskets expand during tightening of the assembly and retain their expanded condition during disassembly. The expansion of the gaskets causes similar expansion of the portion of the retainer clip around the gasket. That expansion is transferred from the portion of the clip around the gasket to the portion of the clip around the end of the tube, with the result that the portion around the tube expands, and then falls off when the fitting is disassembled. In addition, it has been necessary when changing a gasket to move the ends of the tubes farther apart than is optimum in order to move the old gasket axially beyond an end of the clip before moving the gasket transversely, that is, radially, out of the fitting.
By the present invention, the falling of the retainer clip from one of the tube ends or other coupling component during disassembly is avoided by preventing expansion of the portion of the retainer clip which fits around the tube end or other coupling component. In addition, the coupling components need be separated only a minimal amount to permit the changing of a gasket with the retainer clip of the present invention, because the retainer clip and the old gasket can be removed from the coupling component, and a new gasket inserted into the retainer clip and the retainer clip reattached to the coupling component, from the side, without the need for any axial movement.
The retainer clip according to the present invention accomplishes the advantages described above by avoiding the transfer of the expanding force of the gasket from the portion of the retainer clip holding the gasket to the portion of the clip fitting around the coupling component. Furthermore, a side opening in the portion of the clip fixed to the coupling component is sufficiently large to enable the clip to be removed from the coupling component from the side and repositioned on the coupling component from the side.
The retainer clip comprises two generally annular resilient elements which are coaxial with and spaced from one another while being connected by a bridge. One of the resilient annular members fits around the outer wall of the gasket, and the other resilient annular member fits around and clampingly engages the outer wall of the tube end or other coupling component. In one embodiment, the resilient annular member for the gasket has a circumferential extent of substantially a full circle, whereas the resilient annular member for the coupling component has a circumferential extent of approximately two-thirds of a circle. The use of the two connected but axially spaced annular members to fit, respectively, around the gasket and around the coupling component enables the two resilient annular members to act independently of one another and, therefore, to remain secured to two parts of different diameters. As a result of the retainer clip construction, each resilient annular member remains fixed to its respective component part through varying temperature ranges and irrespective of differences in dimensions of the gasket and the coupling components. The retainer clip is maintained in position on the gasket and on the coupling component by friction as a result of the use of a resilient material, for example, spring steel, for the retainer clip. The retainer clip of the invention overcomes the problem of retaining the gasket even though the gasket expands during tightening of the fitting. With face seal fittings using prior retainer clips, when the gasket expands, expansion is transferred to the retainer clip which then spreads and falls off of the coupling or gland component during disassembly.
The ends of the resilient annular member for clampingly engaging the coupling component can be spread apart sufficiently to permit the retainer clip and the gasket to be removed radially from the coupling component and for a retainer clip and new gasket to be inserted radially for installation. The retainer clip of the present invention, in addition to allowing the retainer clip and the gasket to be side-loaded, reduces by one-half the minimum clearance required to remove and replace a gasket.
The retainer clip of the invention is applicable to face seal fittings and gaskets like those shown in U.S. Pat. Nos. 4,838,583 to Babuder et al, 4,854,597 to Leigh, and 5,222,147 to McGarvey to hold the gasket in position before sealing beads on the coupling components engage the gasket.